Superexcited states of oxygen studied by fast-electron impact
- Hefei National Laboratory for Physical Sciences at Microscale, Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui, 230026 (China)
- College of Physical Science, Graduate School of the Chinese Academy of Sciences, P.O. Box 4588, Beijing 100049 (China)
Absolute double differential cross section spectra of O{sub 2} at scattering angles of 0 deg., 2 deg., 4 deg., 6 deg., and 8 deg. below 119 eV have been determined by the angle-resolved electron-energy-loss spectrometer at an incident electron energy of 2500 eV. Some features above the first ionization threshold stand out as the momentum transfer square K{sup 2} increases. Based on our experimental results and theoretical analysis, they are assigned to the optically forbidden Rydberg series of 2{sigma}{sub u}{sup -1}(c {sup 4}{sigma}{sub u}{sup -})np{sigma}{sub u} {sup 3}{sigma}{sub g}{sup -} (n=2-6) and the inner-valence transition of (2{sigma}{sub g}){sup -1}(1{pi}{sub g}){sup 3} {sup 3}{pi}{sub g}<-X {sup 3}{sigma}{sub g}{sup -}, respectively. Furthermore, the observed energy positions of 2{sigma}{sub u}{sup -1}(c {sup 4}{sigma}{sub u}{sup -})np{sigma}{sub u} {sup 3}{sigma}{sub g}{sup -} (n=2-6) confirm a theoretical prediction [Zhong and Li, J. Phys. B 37, 735 (2004)] that the eigenquantum defects show an evident oscillation due to the presence of shape resonance.
- OSTI ID:
- 20650407
- Journal Information:
- Physical Review. A, Journal Name: Physical Review. A Journal Issue: 3 Vol. 71; ISSN 1050-2947; ISSN PLRAAN
- Country of Publication:
- United States
- Language:
- English
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